Burners for gas ranges are often constructed with a gas supply system to get gas to the burner, a burner head (which is sometimes called a flame spreader), and a burner cap. The gas supply system may be a tubular venture or a system including a tube, such as an aluminum tube, potentially along with other mechanical parts which communicate gas to the burner head.
A burner head is often brass or aluminum which is typically either machined and/or cast. Atop the burner head, a burner cap is normally provided. The burner cap is typically steel with a porcelain enamel coating. The burner cap is not normally mechanically fastened to the burner head. In many cases, the burner head rests on the top of the burner head. There can be mating geometry in the burner head and cap, and gravity alone is normally what holds a burner cap at a desired orientation relative to a burner head.
However, under some circumstances, a burner cap can become dislodged from its proper position, such as if an oven door is closed in an aggressive manner. Furthermore, these style burners are often used in recreational vehicles. As a recreational vehicle travels on the road, the burner cap can become displaced or dislodged from its desired position due to the motion of the recreational vehicle as it travels along a road.